Termites are undisputedly the most destructive of all structural insects. Termites are estimated to cause 1.5 billion dollars of damage to structures annually, and an additional one billion dollars is spent on treatment. Depending on the type of termite, a colony can cover as much as 22,000 square feet. These industrious insects work 24 hours a day, gradually eating wood and any other cellulose containing material in their environment. Since they remain hidden within the wood in which they are feeding, in mud tubes, or in the soil, they typically wreak havoc undetected. There are two types of termites, described as i) dry wood termites, and ii) subterranean termites. Of these two types, the subterranean termites usually live in the soil (i.e., soil-borne), from which they build mud tubes to structural wood where they then feed.
Control of soil-borne termites can be accomplished by strategic application of a termiticide to the soil where there is a termite infestation, to provide a continuous chemical barrier in soil surrounding and beneath a structure. However, the final distribution of a liquid termiticide in soil is the result of a series of variables: soil moisture, soil type, solubility of the active ingredient in water, formulation type, and application variables such as volume applied, pressure and nozzle type. The preferred method for control of soil-borne termites is by the application of a termiticide directly to the surface of soil, thereby creating a chemical barrier in the soil when the termiticide leaches into the soil. Termiticides having potential utility in application directly to the surface of soil are applied in the form of a liquid termiticide. A “liquid termiticide” is defined as a composition containing at least one termiticide where the composition is dispensed in an aqueous medium prior to its application to a locus where termite control is needed.
There is a two-fold problem in the art of formulating a liquid termiticide for soil-borne termite treatment. The first problem arises when a liquid termiticide containing a relatively water-insoluble, soil-binding termiticide is applied to the soil there may be gaps, or thinly treated areas, in the desired continuous chemical barrier caused by the immobility of the termiticide in the soil. Termites, therefore, can gain access to food sources/structures through these gaps and thinly treated areas in the chemical barrier. The second problem is that previously available liquid termiticides have relatively low termite mortality rates at low application rates.
Hence, it would be advantageous to provide a liquid termiticide composition for soil treatment that affords a continuous chemical barrier and increased termite mortality at low application rates.